Move eZScript instance into ezpTestSuite
EZP-21829: Avoid notice when overriding a nonexisting variable

When trying to override an INI setting which doesn't exist yet in an INI file, ezpINIHelper triggers a notice that the variable doesn't exist.
EZP-21872: Check system user before executing script
Merge pull request #822 from jeromegamez/EZP-21872_check_system_user

EZP-21872: Check system user before executing script
Merge pull request #812 from jeromegamez/EZP-21829_ezpinihelper

EZP-21829: Avoid notice when overriding a nonexisting variable
Merge pull request #794 from jeromegamez/selfcontained_ezptestsuite

Move eZScript instance into ezpTestSuite, simplifies runtests.php
Generate code coverage reports and publish them to coveralls